/* $Id: symtab.c,v 1.9 2010/11/24 15:12:29 tom Exp $ */

#include "defs.h"

/* TABLE_SIZE is the number of entries in the symbol table. */
/* TABLE_SIZE must be a power of two.                       */

#define		TABLE_SIZE 1024

static bucket **symbol_table = 0;
bucket *first_symbol;
bucket *last_symbol;

static int hash(const char *name) {
	const char *s;
	int c, k;

	assert(name && *name);
	s = name;
	k = *s;
	while ((c = *++s) != 0)
		k = (31 * k + c) & (TABLE_SIZE - 1);

	return (k);
}

bucket *make_bucket(const char *name) {
	bucket *bp;

	assert(name != 0);

	bp = (bucket *) MALLOC(sizeof(bucket));

	bp->link = 0;
	bp->next = 0;

	bp->name = MALLOC(strlen(name) + 1);

	bp->tag = 0;
	bp->value = UNDEFINED;
	bp->index = 0;
	bp->prec = 0;
	bp->class = UNKNOWN;
	bp->assoc = TOKEN;
	strcpy(bp->name, name);

	return (bp);
}

bucket *lookup(const char *name) {
	bucket *bp, **bpp;

	bpp = symbol_table + hash(name);
	bp = *bpp;

	while (bp) {
		if (strcmp(name, bp->name) == 0)
			return (bp);
		bpp = &bp->link;
		bp = *bpp;
	}

	*bpp = bp = make_bucket(name);
	last_symbol->next = bp;
	last_symbol = bp;

	return (bp);
}

void create_symbol_table(void) {
	int i;
	bucket *bp;

	symbol_table = (bucket **) MALLOC(TABLE_SIZE * sizeof(bucket *));

	for (i = 0; i < TABLE_SIZE; i++)
		symbol_table[i] = 0;

	bp = make_bucket("error");
	bp->index = 1;
	bp->class = TERM;

	first_symbol = bp;
	last_symbol = bp;
	symbol_table[hash("error")] = bp;
}

void free_symbol_table(void) {
	FREE(symbol_table);
	symbol_table = 0;
}

void free_symbols(void) {
	bucket *p, *q;

	for (p = first_symbol; p; p = q) {
		q = p->next;
		FREE(p);
	}
}
